Under international law, internal mechanisms have provided the appropriate responses to terrorist acts. The weakness of domestic criminal law is, however, evident in the face of transnational terrorist groups whose operations spreads across many borders. The challenge is compounded when states actively or passively support terrorism. Though traditionally state responsibility has been the vehicle through which pressure is exerted on states sponsoring terrorism, the lethal capabilities of terrorists demonstrated by the 11 September 2001 attacks has fundamentally changed the landscape. The consequences of breaches arising out of a failure by a state to effectively curtail terrorist organisations based or operating out of its territory have expanded sharply, permitting not just financial reparations or other traditional benign countermeasures, but even the extensive use of deadly military force. With the linkage between the terrorist and the sponsoring state becoming crucial to providing states with the justification for a response against rogue states, this article discusses the issue of state-sponsored terrorism and the use of military force in combating terrorism in the context of the UN Charter regime on the use of force.